Turbocharger KKK for AEl: Questions & Answers

Hello.

I'm currently having a problem with the AEL in my Volvo - it's not producing any power.
Around 2000 rpm, you can briefly feel a sensation of air being compressed, but at 3000 rpm, it completely disappears, and there's no more power. The boost pressure doesn't exceed 0.4 bar (according to the measurement), but 1 bar is required.
Based on this, I suspect there's a problem with the turbocharger itself or its related components. I've already swapped everything around the turbo – from one vehicle to the other, including all the valves, sensors, and hoses – but it didn't make any difference.
The LMM (lambda sensor) has been replaced, and the pump setting has been adjusted. Before that, I checked the timing cam (I was thinking that the timing belt might not have been installed correctly, given all the random markings you see on these engines).

The fact is, the engine was replaced at the Volvo dealership 150,000 km ago. Since then, it's been sluggish, according to the former owner. I estimate it's producing around 80 horsepower.

My suspicion was that the wastegate was somehow stuck - the problem is, I'm not familiar with how it works. For example, with the turbos on gasoline engines, you can directly see a valve that opens. On the turbocharger of the old TDI, you see a "hole" and a pipe. Could someone please explain to me how that works?

However, the valve itself seems to be working, as far as one can tell by listening (it opens when I suck on the hose).

I also removed the intake manifold yesterday - the EGR system is active - but surprisingly, it was quite clean.

One of my suspicions is that the turbocharger may have been damaged during the engine failure back then, but this wasn't detected or found. However, the shaft rotates normally (on the intake side).

It's also the case that you can't hear the turbo at all - you usually hear a slight noise when a new one is installed. Therefore, I also assume that the intercooler system isn't broken - the hoses are fine - but if, for example, the radiator bursts, you should see (oil) and hear it, right?

"Someone might have a tip, especially regarding the function of the wastegate. I already have a replacement turbocharger on my workbench, and I'll be installing it today. Hopefully, that will give me a better understanding of the issue and allow me to resolve it."

Okay, here's the translation:

Thank you.
Sure, here is the translation of the text from German to English:

"Hello"

Okay, I'm ready. Please provide the German text you want me to translate.

dieselschrauber wrote:

/viewtopic.php?t=3101

THANK YOU!

Hey.

"I replaced the turbo today. Now I understand how it works. Unfortunately, the replacement didn't make any difference at first. I've tried everything – now it seems like the problem might be with the ESP or the injectors. When I use a chip tuning, there's only a slight improvement; I can hear the turbo, but it stops boosting around 3000 rpm."
There's nothing more that can be done.
However, it then becomes very quiet, which is why I suspected from the beginning that the pump was malfunctioning. But the settings are correct.
Could it be that something is wrong with the injection molding machine, or is there a problem with the pump?
I doubt that the pump or the nozzles are the problem, but I've already replaced almost everything else.
Between the mass airflow sensor and the turbo, there's a sensor - the part number says it's a PTC of some kind - that wasn't plugged in. I found the connector, and it was completely corroded - so it had been "forgotten" to be plugged in for a long time. At first, I thought I had found the problem, but it didn't change anything .

Does anyone have any more advice for me?

BTW, could it be that something is wrong with the engine? Should I consider having a compression test done? But all of this seems inconsistent, like the turbocharger just isn't kicking in - what do you think?

THANK YOU

best regards, uwe

Quote:

Should I, for example, consider having a compression test done?

No - why would I? As long as it starts, it has compression.

Obtaining measurements of parameters such as boost pressure, EGR, and air mass would be beneficial.
What does the error memory contain?

Are the airways (intake and exhaust tracts) clear? Is the camshaft okay?

Hello.

"Thank you."

The system requests a boost pressure of 1 bar, but it only delivers 0.4 bar.

The intake manifold and exhaust manifold are clear. The mass airflow sensor (MAF) has been replaced (I have several identical vehicles, and I've already swapped almost everything between them for testing).

The exhaust system itself remains, but the question is: is there a mouse sleeping in the exhaust, or is the catalytic converter clogged?

I also have some nozzles lying around; I'll replace them tomorrow. And the wiring harness on the engine too - it seems there's something wrong with the wiring.

Attached is a test measurement.

THANK YOU

Sure, here is the translation of the text from German to English:

"Hello"

"If the exhaust was blocked, I believe the turbocharger pressure would initially appear normal, but then drop off at higher RPMs. It might be beneficial to examine the catalytic converter more closely."

roorback wrote:

A pressure of 1 bar is requested, but only 0.4 bar is delivered. The intake manifold and exhaust manifold are clear, the mass airflow sensor (MAF) has been replaced (I have several identical vehicles, and I've already swapped almost everything with a test vehicle).

1. What happens if you disconnect the control hose at the turbocharger housing? Then the wastegate should be closed, and the boost pressure should not be limited. If the boost is still too low, then with a working turbocharger and no exhaust leaks before the turbine, it can only be due to a lack of drive (exhaust flow). }

"Do you observe significant discrepancies between the (high) average fuel consumption reading and the (lower) fuel consumption during nighttime operation? If so, there's likely a bottleneck somewhere between the electronics and the fuel injection system."

Hello.

Thank you for the tips. If I disconnect the hose (which was already broken anyway and probably wasn't working), it doesn't make much of a difference. I think that if I disconnect it, it might even produce more than 1 bar – maybe even too much... so I have to be careful either way. But there's nothing I can do.

Regarding fuel consumption, I can't say much yet – the onboard computer shows a very low value. I drive my commute and it shows around 4.0 liters, whereas it would normally be around 6.0 liters. However, this doesn't necessarily mean much to me, as it could be adjusted in the ESP settings.

Currently, it runs reasonably well up to around 3000 RPM. With the other control unit and chip tuning, it stops working beyond that point. It also seems to be getting better over time...

I need to take a look at the exhaust - I've been thinking about how I could check it, but I can't come up with anything. Maybe I could leave the turbo completely open sometime? And maybe just take it for a short drive?

I do have a KAT (catalytic converter) and exhaust here, so I could swap them. Basically, I have everything here; I still drive two of these cars and have several disassembled ones "in stock." This makes things "cheaper," but not easier . So, I've pretty much replaced everything around and on the turbo.

Here's what I was thinking: I could install a modified LMM (lambda sensor) that always reads a certain value, and then block the throttle valve in the open position. Theoretically, this would force the software to always allow the maximum fuel flow, which would likely cause excessive soot buildup, but it might work.

Otherwise, what remains is:

* Nozzles (this is quick to do, coming up next).
* ESP
* Wiring harness

Thank you all for your great help.

PS: One more question - if the intercooler had burst, you would hear it - the turbo would still spin up - and, I mean, it would be oily - so you would notice it - right? The intercooler is located in the center of the engine bay and is screwed in, so you can't really see it...

roorback wrote:

I need to take a look at the exhaust - I've been thinking about how I could check it, but I can't come up with anything. Is it possible to leave the turbo completely open? And can I take it for a short drive?

As long as the exhaust gases don't flow directly onto heat-sensitive parts, you can try for a short time to see if it accelerates better like that.

Quote:

What I was also thinking about - installing a modified mass airflow sensor (MAF), blocking the throttle valve in the open position - then, theoretically, the software should always release the full fuel amount - it would produce a lot of soot, but it should work, right?

If the MAF sensor is the cause: yes.

Quote:

If the intercooler had burst, you would hear it - the turbo would still be spinning up - and, I mean, it would be oily - so you would notice it - or would you? The intercooler is in the center, screwed in, as part of the package, and you can't really see it...

Especially, it would have to whistle or roar noticeably.
You can also detect turbocharger air leaks by comparing the actual intake manifold pressure (LD-Ist) with the actual air mass flow (LuMa-Ist), *provided* that both sensors are functioning correctly and the normal relationships are known. Unfortunately, I don't have any information about the AEL. For the 1.9 TDI engines, the relationship typically falls within the range of 0.40 to 0.50, depending on the intake manifold pressure, turbocharger, and engine speed.

THANK YOU.
I'm curious to see how "quiet" the TDI will be without an exhaust.

I will report back later.

By the way, I read the link that was posted earlier, but I don't understand the following:

Code:

Der für die volle Leistung erforderliche höhere Ladedruck wird erreicht, indem Ladedruck und Außendruck (von einem Abgriff im Bereich Ladereingang / Luftfilter) per Magnetventil im Schlauchsystem vermischt werden und der reduzierte Druck an die Membrandose geleitet wird. Dadurch öffnet das Wastegate erst bei entsprechend höherem Ladedruck.

The wastegate opens at 0.6 bar and limits the boost to 0.6 bar. That's exactly my target boost pressure. How does the solenoid valve work (which one?) to achieve the required pressure? Perhaps the problem lies there...?

"Thank you!"

roorback wrote:

So, the wastegate opens at 0.6 and limits the pressure to 0.6. That's exactly my desired boost pressure. How does the (which?) solenoid valve work to achieve the required pressure? Perhaps the problem lies here...?

You can find the valve by tracing the thin pressure hose from the turbocharger back.

However, if the problem persists even without the pressure hose connected to the turbocharger, the valve can be ruled out as the cause, because in that case, the wastegate should not open.

Okay, that's the golden valve. Thank you.

Quote:

The controlled wastegate turbocharger (e.g., in the 1Z) has a conventional pressure-actuated diaphragm, which, when Approximately 0.6 bar, the wastegate opens and prevents a further increase in boost pressure. The higher boost pressure required for full performance is achieved by combining boost pressure and atmospheric pressure (from a...). The air intake/air filter area has a solenoid valve in the hose system that mixes in the air. The reduced pressure is directed to the membrane dose.

As a result, the wastegate only opens at a correspondingly higher boost pressure.
Source: https://community.dieselschrauber.org/en/viewtopic.php?t=3101

Hose disconnected from the wastegate actuator -> maximum boost pressure of 0.6 bar is possible. If less boost is achieved, it could be due to the wastegate not closing properly, the turbocharger not having enough "drive" (due to insufficient fuel injection), or a leak in the intake system. A common location for leaks is the underside of the 90-degree rubber elbow directly at the intake manifold.

If the wastegate hose is connected directly to the pressure side of the turbocharger, bypassing the boost control valve (if you're unsure where this is, follow the hoses), the wastegate will remain closed, and the boost pressure will become too high. Perform a test drive very cautiously and monitor the boost pressure.

Best regards, Rainer.

Hello.

I've read it, but I don't understand it because it seems contradictory.
I assumed that the pressure sensor for the wastegate opens under pressure – "open" for me means bypass, which implies lower boost pressure.

So, if I disconnect the cable, there will be no pressure, the wastegate will remain closed, and the boost pressure should be fully present.
When I build up boost, the wastegate opens, and the boost pressure is reduced.

There are also loaders, but in those, it's the opposite - they operate using negative pressure.

Where is my flaw in reasoning?

"Thank you!"

best regards, uwe

Quote:

I have read it, but I don't understand it because it is contradictory. I assumed that the pressure sensor for the wastegate opens under pressure – "open" for me means bypass, which implies lower boost pressure. So, if I disconnect the cable, there will be no pressure, the wastegate will remain closed, and the boost pressure should be fully present. If I build up pressure, then the wastegate is open, and the boost pressure is reduced.

Not exactly. The pressure generated by the turbocharger (hence the connection on the pressure side) is additionally added to the ambient air pressure and directed to the diaphragm on the wastegate, so that it remains.
If no pressure is applied to the wastegate actuator, it will open automatically starting at approximately 0.6 bar of boost pressure, as the exhaust gases will then push against the wastegate.

Best regards, Rainer.